1. Field of the Invention
The present invention relates to a method of producing single crystal silicon by the Czochralski process, in particular, to a method of producing single crystal silicon having relatively low resistivity.
2. Description of Related Art
There has been a demand, in recent years, for single crystal silicon having relatively low resistivity to improve performance of a semiconductor device product.
Resistivity of a silicon wafer is generally determined in accordance with an added amount of a dopant (s).
For example, in a case of N-type single crystal silicon, a dopant such as a very small amount of phosphorus (P), antimony (Sb), arsenic (As) and germanium (Ge) is added to a molten silicon raw material for the purpose of controlling resistivity.
Regarding decreasing resistivity of single crystal silicon, JP 2005-314213 Laid-Open proposes producing single crystal silicon having resistivity of 2.0 mΩ·cm or so by using arsenic as dopant and doping silicon with arsenic such that a mol ratio of silicon with respect to arsenic is in the range of 45 to 50%.